macOS processes › Core system
What is notifyd on Mac?
notifyd is a low-level macOS service that passes simple signals between processes, such as “the network changed” or “the time zone changed”. It has nothing to do with the notifications you see on screen.
What it does
Processes register interest in named events, and notifyd tells them when those events fire. Almost every part of macOS uses it, and it's built to be very light. A single copy runs for the whole system.
Why it gets busy
- A process posting the same signal thousands of times a second because of a bug.
- Bursts of system activity, such as right after login or waking from sleep.
Is it safe to quit?
Quitting it would break signaling between system processes. Restarting your Mac is the clean way to reset it.
How to calm it down
- Restart your Mac if notifyd stays busy; it starts fresh.
- If the load returns, check which apps are new or recently updated, and update or remove them.
In SystemWatch
SystemWatch explains notifyd in plain language, and History shows whether it actually stayed busy or only spiked for a moment.
